I've discovered that the tempo of the song "Lose Yourself" by Eminem is the perfect running pace for me. When I make sure my right foot hits every beat (left foot every eighth note) I get into a rhythm and could just go forever.
So today I put it on my playlist 4 times.
It got to the point where I had trouble if a different song came on.
So, for now, I guess I have to run to this song. All. The. Time. (Or a metronome set at 88 bpm.)